This invention relates to lawn rakes, and more specifically to broom-type rakes having teeth of either bamboo or spring steel construction.
The problem in lawn rake design is to provide, in combination:
1. Terminating of the rake teeth on the same straight line transverse to the rake axis, and with all of the teeth simultaneously engaging the surface to be raked across the full spread of the rake teeth, so that the tool may rake cleanly from and close against a laterally straight vertical edge or surface, such as of a structure, wall, curb or garden; and so that through no matter what angles or attitudes it is swung or side-stroked, the rake maintains full ground tangency without either ground digging by the teeth at the center of, or ground-clearing of the teeth at the sides of, the teeth spread.
2. Duplicate or uniform length teeth, so the rake requires but a single same tooth specification or length.
3. Separate or individual tines or teeth, that are unsplit, untwisted and unturned, and fabricatable equally of bamboo or steel.
4. Teeth-handle joining without thinning, splitting, twisting or drilling of the teeth, and with flat planar arraying as opposed to overlapping or bunching of the teeth at the apex of the spread.
5. Integral constructing and flat-forming of the teeth-handle socket head, and extending of the socket head or partial sheathing thereby of the teeth, for stiffening but not fracture-inducing of the teeth some distance away from their handle ends and equi-distantly from their working ends, but without resort to means external to the flat fastening.
6. Durability of the teeth-handle fastening, and more particularly provision of a rugged, integral socket head securing without weakening either the handle or the teeth.
7. A proper balance in the teeth spread of flexibility or resilience with stiffness.
8. Capability of manufacture at low cost and with a minimum number of parts and manufacturing steps.
Broom type lawn or leaf rakes such as here concerned are still principally of the half century old design of U.S. Pat. No. 1,989,815, which does not solve the problem, failing as it does to supply any of the foregoing requirements in full measure. More particularly, the design of U.S. Pat. No. 1,989,815 has an arc-fan instead of the wanted "A" or triangular shape of teeth spread; requires the use of split strips; bundles and weakly clips the strips to the handle at the teeth apex; employs a teeth stiffener which is weakly attached to the handle; causes fracturing of the teeth at their strip-split junctures; and engages the teeth at non-uniform distances from their working ends. And as indicated in U.S. Pat. No. 2,018,311, with this design the stiffening of the teeth away from the handle requires the use not only of the usual cross bar, but also the use of an additional wire coil stiffening device.
A more durable, relatively flat teeth-handle mounting has been achieved with metal teeth rakes such as of U.S. Pat. Nos. 2,137,795 and 2,316,168, but this has required twisting and turning of the teeth in a cost-adding way not attainable with bamboo, and has required further the addition to the rake structure of a heavy, cumbersome, costly, spring stiffener assembly that precludes compact stacking and storage.
Various attempts have heretofore been made with bamboo teeth rakes as well, to supply the wanted durable, flat or co-planar teeth-handle fastening, such as illustrated by U.S. Pat. Nos. 1,880,580; 2,007,609; 2,040,205; and 2,321,489. But these latter designs have all been unsuccessful, or rejected by the art for their failing each to supply several other of the foregoing requirements.
Thus none of this latter group of patents supplies the wanted "A" or triangular tooth spread shape, all employing instead the conventional arc-fan. And in all cases the teeth-handle mounting is an ungainly, cumbersome contrivance that denies the proper balance of resilience with stiffness, that lacks the wanted yielding support of the teeth away from their inner ends, and that lacks the required form of handle receptacle, for durable, co-planar connection without drilling of the same.
There have been other attempts at improving on the unacceptably weak teeth-handle mounting of U.S. Pat. No. 1,989,815, such as of U.S. Pat. Nos. 2,122,359; 2,497,192; and 2,519,714, but these have all retained the unwanted teeth overlapping and bundling at the apex, and have failed to supply the straight transverse line of the teeth, or the stiffening by the socket of the teeth sufficiently away from their inner ends, and have required splitting both of the teeth and of the handle, or involved weak, fracture-causing pin mounting of the handle and teeth stiffener.
Thus, this invention originally and uniquely solves the stated problem, and more particularly is the first and only to supply each and every of the above enumerated lawn rake requirements.